1. Field of the Invention
The invention relates to a method of manufacturing surface-discharge-scheme alternating-current-type plasma display panels, and more particularly, to a method of forming components, such as a dielectric layer and the like, of the plasma display panel.
The present application claims priority from Japanese Application No. 2002-68149, the disclosures of which are incorporated herein by reference for all purposes.
2. Description of the Related Art
At the present time, surface-discharge-type AC plasma display panels (hereinafter referred to as xe2x80x9cPDPxe2x80x9d) have received attention as large-sized flat color-screen displays, and have increasingly become commonly used in ordinary homes.
FIGS. 6 and 7 illustrate the configuration of a surface-discharge-type alternating-current PDP which has been proposed by the present applicant. FIG. 6 is a schematically perspective view of the proposed PDP when the front glass substrate is disassembled from the back glass substrate. FIG. 7 is a sectional view taken along the column direction of the PDP at a central point in discharge cells.
The PDP in FIGS. 6 and 7 includes a front glass substrate 1 having a back surface on which a plurality of row electrode pairs (X, Y) are arranged at regular intervals in the column direction and each extends in the row direction. Each of the row electrodes X and Y forming the row electrode pair (X, Y) is constructed of T-shaped transparent electrodes Xa (Ya) and a bus electrode Xb (Yb) extending in the row direction. The transparent electrodes Xa and Ya are opposite to each other with a discharge gap g set at a required distance and interposed in between.
A dielectric layer 2 is also formed on the back surface of the front glass substrate 1 so as to cover the row electrode pairs (X, Y). In turn, additional dielectric layers 3 are formed on the back surface of the dielectric layer 2, and covered with a protective layer (not shown) made of MgO.
Further, a black additional layer 3A formed of a black light-absorbing material is formed on a portion of the additional dielectric layer 3 and opposite a zone between the bus electrodes Xb (Yb) of the back-to-back row electrodes X (Y).
On a surface of a back glass substrate 4 on the display screen side, a plurality of column electrodes D and a column electrode protective layer 5 covering the column electrodes D are formed, and then a partition wall 6 is formed on the column electrode protective layer 5.
The partition wall 6 is constructed of pairs of first transverse walls 6A, pairs of second transverse walls 6B and transverse walls 6C. The pairs of first transverse walls 6A and the pairs of second transverse walls 6B are arranged in alternate positions in the column direction. The first or second transverse walls 6A or 6B in each pair are positioned back to back in between adjacent display lines.
A clearance r is formed between the second transverse wall 6B and the protective layer covering the additional dielectric layer 3.
The opposing first transverse walls 6A, the opposing second transverse walls 6B and the vertical walls 6C of the partition wall 6 partition the discharge space defined between the front glass substrate 1 and the back glass substrate 4 into display discharge cells C1. Red-, green-, and blue-colored phosphor layers 7 are each formed in the display discharge cell C1 and are arranged in order in the row direction.
Further, a protrusion rib 8 protrudes into a space formed between the two back-to-back second transverse walls 6B and raises a part of the column electrode D, located between the two second transverse walls 6B, and the column electrode protective layer 5 covering this column electrode D, to cause them to be in contact with the black additional layer 3A.
Thus, two addressing discharge cells C2 are formed on both sides of the protrusion rib 8, and each communicates with the corresponding display discharge cells C1 through the clearances r.
When additional layers of a dielectric layer are formed in multilayer formation as in the case of the above PDP, a lamination of the additional layers (for example, the additional dielectric layer 3 and the black additional layer 3A) on the dielectric layer is carried out by prior art methods typically including the following steps.
A prior art method using a photosensitive dielectric film for forming the lamination of the additional layers of the dielectric layer is here described.
Initially, as illustrated in FIG. 8A, a photosensitive dielectric film F1 is laminated on the dielectric layer 2 of the glass substrate 1 on which the row electrodes (not shown) and the dielectric layer 2 are formed. Then, as illustrated in FIG. 8B, a mask M1 having through-holes M1a formed therein in correspondence with positions and shape of additional dielectric layers 3 to be formed is laid on the photosensitive dielectric film F1. The photosensitive dielectric film F1 is exposed to light through the mask M1 to undergo patterning.
Then, as illustrated in FIG. 8C, the photosensitive dielectric film F1 is developed to remove the unexposed regions, and then the remaining exposed regions are burned to form additional dielectric layers 3.
Then, as illustrated in FIG. 8D, a photosensitive dielectric film F2 is laminated on the dielectric layer 2 and the additional dielectric layers 3 which is formed as described.
Then, similarly, as illustrated in FIG. 8E, a mask M2 having through-holes M2a formed therein in correspondence with positions and shape of additional dielectric layers 3A to be formed is laid on the photosensitive dielectric film F2. The photosensitive dielectric film F2 is exposed to light through the mask M2 to undergo patterning.
After this patterning process, as illustrated in FIG. 8F, the photosensitive dielectric film F2 is developed to remove the unexposed regions, and then the remaining exposed regions are burned to form additional dielectric layers 3A.
However, in the case of the above prior art method using a photosensitive dielectric layer for forming the additional layers of the dielectric layer in multilayer form, when the photosensitive dielectric film F2 is laminated in order to form the additional dielectric layers 3A which is the second layer, protrusions and hollows presented by the pre-formed additional dielectric layers 3 cause crinkles in the photosensitive dielectric film F2, and therefore adhesion between the photosensitive dielectric film F2 and the dielectric layer 2 is insufficient, giving rise to a problem of peeling in the developing or burning process.
Further, with this prior art method, the initially formed additional dielectric layers 3 are shrunk in shape in the burning process. This shrinkage results in the strict necessity for high precision in alignment in the patterning process for the second layer for the additional dielectric layers 3A. The uneven top surfaces of the additional dielectric layers 3 after undergoing the burning process gives rise to a problem of the sliding of the photosensitive dielectric film F2 during the developing process for forming the second layer for the additional dielectric layers 3A.
The prior art method has further problems of an increase in manufacturing costs and a decrease in efficiency of working because of the increase in manufacturing steps due to repeating the exposure, development and burning processes for forming the first layer and the second layer which are to be the additional layers of the dielectric layer.
The prior art method has yet another problem of a relatively positional deviation produced between the pattern of the row electrode and the additional layers of the dielectric layer because the repeating of the burning processes creates deformation or shrinkage of the glass substrate 1.
Another prior art method using pattern printing for multilayer formation of additional layers of the dielectric layer is now described. First, as illustrated in FIG. 9A, a low-melting glass paste 3xe2x80x2 is pattern-printed and dried onto a predetermined position on the dielectric layer 2 of the glass substrate 1 on which the row electrodes (not shown) and the dielectric layer 2 are formed, so as to be shaped in correspondence with the shape of the additional dielectric layer to be formed.
In addition, as illustrated in FIG. 9B, another low-melting glass paste 3Axe2x80x2 is pattern-printed and dried onto a predetermined position on the pattern-printed and dried low-melting glass paste 3xe2x80x2 so as to be shaped in correspondence with the shape of the additional dielectric layer to be formed.
After that, the low-melting glass pastes 3xe2x80x2 and 3Axe2x80x2 formed in double-layer formation are burned to form two laminated additional dielectric layers.
However, the above prior art method using pattern printing also has problems of the difficulty in alignment between the additional layers of the dielectric layer in multilayer formation because of the low precision of pattern printing, and also of the likelihood of low precision in the multilayer dimensions of the formed additional dielectric layers because of wide variations in film-thickness of the low-melting glass paste 3xe2x80x2 and 3Axe2x80x2 formed by pattern printing.
The present invention has been made to solve the various problems arising in the prior art processes of multilayer lamination of additional layers of a dielectric layer in plasma display panels as described above.
It is therefore an object of the present invention to provide a method of manufacturing plasma display panels capable of forming and laminating dielectric layers in multilayer formation with a reduced number of processes and also providing a high precision.
To attain the above object, a manufacturing method of plasma display panels according to the present invention relates to a manufacturing method for forming lamination of a plurality of dielectric layers on a substrate of the plasma display panel, having a first feature of including the steps of: a forming process for forming a photosensitive glass material layer forming the dielectric layers; a patterning process for exposing required parts of the photosensitive glass material layer, formed by the forming process, to light; repeating the forming process and the patterning process for each of the photosensitive glass material layers to be formed and laminated on the substrate; a developing process for concurrently removing unexposed parts from all of the formed and laminated photosensitive glass material layers after completion of the forming process and the patterning process for each photosensitive glass material layer; and a burning process for concurrently burning all of the formed and laminated photosensitive glass material layers having been subjected to the developing process.
With the manufacturing method for plasma display panels according to the first feature, for example, when additional layers of a dielectric layer covering discharge electrodes formed on a substrate of the plasma display panel are laminated in multilayer form on the dielectric layer in order to limit the spreading of a discharge, the forming process for a photosensitive glass material layer, and the patterning process for exposing to light the photosensitive glass material layer, formed in the forming process, to pattern it with dielectric layers of a required shape at required positions are repeatedly performed on each of the photosensitive glass material layers for multilayer formation of the dielectric layers to be laminated.
After all of the required photosensitive glass material layers have been formed, and the patterning performed thereon, the laminated photosensitive glass material layers all undergo at the same time the developing process for removing the parts of the photosensitive glass material layer unexposed in the patterning process so that the remaining exposed parts will form dielectric layers such as the additional layers having the required shape, and undergo the burning process for solidifying the photosensitive glass material layers provided by the developing process.
As described above, according to the first feature, the developing process is performed concurrently on all of the photosensitive glass material layers after completion of the forming process for each of the multilayered photosensitive glass material layers. Hence, each of the second and later photosensitive glass material layers is formed on a photosensitive glass material layer that has not experienced the developing process. The resulting flat formation of the top surface of the photosensitive glass material layer leads to a significant increase in the positional precision between the dielectric layers to be laminated in multilayer form, as compared with the prior art manufacturing methods.
The burning process is finally performed concurrently on the photosensitive glass material layers. The photosensitive glass material layers are not burned repeatedly as was done in prior art methods, to prevent an inferior precision in alignment and the occurrence of positional deviation between the electrodes formed on the substrate and the dielectric layers laminated in multilayer form.
Further, the developing process and the burning process are each performed only one time, leading to simplification of the manufacturing process of the plasma display panel, and naturally reduction in the manufacturing cost.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the first feature, a second feature that the photosensitive glass material layer is formed of glass materials having lead oxide and silicon dioxide as their main components, and glass materials including photosensitive resin made from an acrylic-type monomer or oligomer.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the first feature, a third feature that the photosensitive glass material layer is burned at temperatures in the vicinity of a softening point of the glass materials forming the photosensitive glass material layer.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the third feature, a fourth feature that the burning temperature ranges from 560 degrees C. to 580 degrees C.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the first feature, a fifth feature that a non-photosensitive glass material layer is formed on the substrate prior to the forming of the initial layer of the photosensitive glass material layers, and undergoes the burning process concurrently with the laminated photosensitive glass material layers.
With the manufacturing method for plasma display panels according to the fifth feature, the non-photosensitive glass material layer forming the dielectric layer covering the electrodes formed on the substrate, is formed on the substrate prior to the forming of the photosensitive glass material layers to be laminated in multilayer form. Then the burning process for the non-photosensitive glass material layer is performed concurrently with the burning process for the laminated photosensitive glass material layers.
Therefore, positional deviation between the dielectric layers after their formation is prevented and simplification of the manufacturing process to reduce the manufacturing costs is provided.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the fifth feature, a sixth feature that the non-photosensitive glass material layer is formed of glass materials having lead oxide and silicon dioxide having softening point temperatures of about 560 degrees C. as their main components, and glass materials including non-photosensitive resin made from an acrylic-type polymer.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the fifth feature, a seventh feature that the non-photosensitive glass material layer and the photosensitive glass material layer are formed of the glass materials approximately equal to each other in softening point temperatures.
With the manufacturing method for plasma display panels according to the seventh feature, the use of glass materials roughly equal in softening point temperature to form the non-photosensitive and photosensitive glass material layers allows the burning process to be performed concurrently on the non-photosensitive and photosensitive glass material layers.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the fifth feature, an eighth feature that the dielectric layer provided by the photosensitive glass material layer is an additional layer of the dielectric layer provided by the non-photosensitive glass material layer.
With the manufacturing method of plasma display panels according to the eighth feature, at required positions on the dielectric layer provided by the non-photosensitive glass material layer, the photosensitive glass material layer forms the additional layers of required dimensions allowing for limitation of the spreading of a discharge in the discharge space, or the like.
To attain the aforementioned object, the manufacturing method for plasma display panel has, in addition to the configuration of the first feature, a ninth feature that the formation of the photosensitive glass material layer on the substrate in the forming process is carried out by pre-coating of a glass paste on a supporting film and then bonding of the resulting photosensitive glass material layer onto the substrate by pressure.
With the manufacturing method for plasma display panels according to the ninth feature, in order to form the photosensitive glass material layer on the substrate, a glass paste is not coated directly on the substrate, and alternatively the glass paste is previously coated on the supporting film and dried thereon to prepare a film having a photosensitive glass layer with a required thickness formed thereon. The film-form photosensitive glass material layer is bonded by pressure while the supplying film is being peeled from it, to form a photosensitive glass material layer on the substrate.
As a result, the manufacturing process of the plasma display panels is simplified and the photosensitive glass material layer has an advantage of being formed to a desired and uniform thickness on the substrate.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the ninth feature, a tenth feature that while the supporting film is peeled from the photosensitive glass material layer formed on the supporting film, the photosensitive glass material layer is bonded on the substrate by pressure in a heated state by use of a roller.
To attain the aforementioned object, the manufacturing method for plasma display panels has, in addition to the configuration of the first feature, an eleventh feature that in the patterning process, each of the photosensitive glass material layers is exposed to light through a mask having through-holes corresponding to positions and shape of the dielectric layers provided by the photosensitive glass material layer.
With the manufacturing method for plasma display panels according to the eleventh feature, for each of the dielectric layers to be laminated in multilayer form, a mask having the through-holes corresponding to the positions and shape of the individual dielectric layer can be prepared in advance or alternatively can be formed on the corresponding photosensitive glass material layer. Each photosensitive glass material layer is exposed to light through the corresponding mask in the patterning process in order to be readily laminated as a dielectric layer of a desired shape in a desired position.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.